http://178.254.23.111/~pub/masternode_count.png
Now remember that each masternode has a collateral of 1000 Dash, which means Dash combined MN collateral amount = 4,9 million Dash (sitting in cold wallets / hardware wallets, not circulating)
Dash circulating supply according coinmarketcap = 8,4 million Dash - 4,9 million Dash = 3,5 million Dash effectively in circulation (circulating freely in markets / exchanges).
Done! 4909